This invention relates to devices for tensioning running textile yarns, which term is intended to encompass all types of textile strands, filaments and the like; and is more particularly directed to tensioning devices of the type wherein the yarn passes between a spherical ball-like element and an underlying member supportively seating such element. Illustrative tensioning devices of the foregoing general type are disclosed in U.S. Pat. Nos. 3,753,535, 2,373,513, 2,222,921, 1,785,987, 1,490,512, 1,432,399, 1,408,560 and 1,040,185 and in British Patent No. 299,620.
Yarn tensioning devices are employed in large quantities in a wide variety of textile manufacturing or processing operations. The operating characteristics required of such devices may differ markedly from one use-application or operational environment to another, depending upon such variable factors as the size, texture and speed of the particular yarn to be tensioned, and the magnitude of the tension to be induced in such yarn. For example, the proper tensioning of a yarn containing slubs or kinks therein and being used in, say, a high-speed knitting machine, involves factors and problems not present in the tensioning of a smooth yarn being wound upon a cone or other receiving element. It is therefore highly desirable for a tensioning device to be so adjustable that its operating characteristics can be correlated to the particular demands of any one of the many different operational-environments in which its use might be required. It is also highly desirable for such adjustment to be realizable quickly and easily, without the use of any tools or the like, even by only semi-skilled personnel. Further, the aforesaid capability of the tensioning device for such adjustment should be realized without impairing the device's durability or reliability, and without greatly increasing its cost.